#airgrilles com

12" X 12" AirGrilles.com Heavy Duty Steel Return Air Filter Grille Removable Face/Door for 1-inch Filters HVAC Duct Cover Grill, White Outer Dimensions: 14 5/8"W X 14 5/8"H for 12x12 Duct Opening

20"W x 20"H Duct Opening Size Steel Return Air Filter Grille Detachable Door, for 1-inch Filters, Vent Cover Grill, White, Outer Dimensions: 22 5/8"W X 22 5/8"H for 20x20 Opening